Petroleum distillate fuels



petroleum pipe lines, oil cargo vessels, etcl 'dustrial fuel oils and the like.

PETROLEUM DISTILLATE Fred B. Fischl, Springfield, and George A. Weisgerber,

Iselin, N. J., assignors to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Application May 25, 1955 Serial No. 511,102

9 Claims. (Cl. 44-72) to inhibit the corrosion of ferruginous metals which are in contact with water. The invention is especially adapted for the stabilization of cracked fueloils which are maintained in storage for extended periods of time; and the invention is further particularly adapted for the prevention and reduction of corrosion in fuel storage tanks,

Petroleum distillate fuels as such are well known in the art and include heating oils, kerosenes, diesel fuels, in-

These fuels constitute major products in the petroleum refining industry; and,

accordingly, considerable effort has been expended by v this industry in an effort to maintain and improve the United States Patent I quality of these products. In years past, these fuels consisted primarily of straight-run stocks, but in morerecent years it has been necessary to include substantial amounts of cracked stocks within the fuel. With the inclusion'of these cracked stocks, the refiners have encountered several lem, petroleum refiners have resorted to a number of tactics including the utilization of new refining techniques as well as the use of various additives. Theseadditives have included metal naphthenates, metal sulfo'nates, salts of alkyl phenol sulfides, various amine compounds and the like. These materials have been successful to a degree in overcoming the sedimentation problem, but a continuing search is still in progress for still better additives to serve this function. In this connection it has recently been observed that some of the sediment-stabilizing agents are effective in varying degrees in preventing the formation of sediment in fuel oils depending apparently upon'fthe amount and origin of the cracked constituents in the oil's.

Of particular interest is the observation that, when these agents are employed in more extensively cracked stocks or in fuel oils that contain large amounts of cracked.

stocks, the degree of sedimentation is often actually greater than would be expected even without the: sedimentstabilizing agents. The reason for this anomalous condition is not known as yet, but it appears that an ineffective amount of stabilizingagent fails, toprevent the Patented Nov. 11, 1958 "sediment from forming; and when the sediment does form, ittends to precipitate the agent along with it. Thus, it is extremely desirable to find and develop sediment-stabilizin'g agents which are more effective ininhibiting-sediment formation thanare the materials that are presently employed for this purpose. t

In addition to the sediment forming problem, a rather serious corrosion problem exists in storage tanks, oil

cargo vessels, pipelines, etc. which are employed for the 'storage and/or transportation of distillate fuel oils. It

will be appreciated and it is a well known fact in the art that these storage vessels and transportation media generally contain small amounts of water in addition tothe distillate fuel oils, and it has been observed that the presence of the water (along or in conjunction with the fuel oils) gives rise to a peculiar form of corrosive action. The type of corrosion is perhaps best designated as a pitting action in that the metallic surfaces affected are penetrated by relativelysmall diameter, but deep. pits. When these pits aredeep, enough to penetrate entirely .through the metal container or vessel, leakage or failure "of the Vessel or container may occur. In any event, extensive fuel losses may occur and repair of the'vessels or pipe lines. must be made. All ofthese'results are expensive, and his eminently desirable to avoid their occurrence.

It is an objectof the present invention to overcome and avoid the sediment formation and corrosion problems that are associated with the manufacture and handling of petroleum distillate fuels. It is especially an object of the invention to provide distillate fuel oils that contain in excess of 10 vol. percent cracked stocks with minor proportions of a complex additive agent which is capable of simultaneously preventing both of the aforementioned In accordance. with the present invention, a petroleum distillate fuel oil and particularly one containing'at least :10 vol; percent cracked stocks is stabilized against sediment formation and is also simultaneously endowed with corrosion inhibiting qualities by the;incorporation .therein of a minor but effective amount of a complex reaction product formed by reacting a particular type of 'sulfonate compound with particular inorganic salts; The precise sulfonates and inorganic salts that may be employed for thispurpose will be described in detail later in this description. h As mentioned earlier, the fuel oil componentsofthe present fuel oil compositions are petroleum distillatefractions such as are commonly designated as kerosenes,

dieselfuels, distillate heating oils, distillate industrial fuel oils, etc. The invention has application to those petroleum distillate fuel oils that boil within the range from about 325 F. to 675 F. and that possess specific gravities of about 23 to 40 API. Typicalinspections of such petroleum distillates are as follows:

As stated above, fuel oils that are particularly benefitted by this invention are characterized by possessing at least about 10 vol. percent constituents that are derived from cracking operations. The fuel oils may be entirely com: posed of cracked stocks, butthe invention is especially directed toward the stabilization of those fuel oils that contain about 20 to vol. percent of such stocks.

I It will be appreciated that the cracked componentsof the present fuel'oil compositions may be derived impart 'be' asimplebenzene ring.

or entirely from th ermal and/or catalytic type cracking operations.

Thus, typical fuel oils that may be employed in accordance with the invention are fuel oils that; contain from 20 to '90.-vol. -;p er;cent-s,traighti%,run

. omponents; ;10 80 vol. percent wthermally .craeked component s,-;an d 0. to 80.vol. pereent c a lv iea wrac ed .-co-mponents. It will beunoted that stock U d v Hiram other; I operations such as.- reforming hydro -o r:r m f ng, hydrofining, coking, steam cracking and thesl ke rnaymlso be utilized. 9

The inorganic, salts, that are aused ingthepractice of the; present. invention include. the Tsalts; of nitrous I acid,

'whereinthe cationioor.metalportions of-. the, saltsarc selected; frorn -the, group ,consisting ofv zthe flamm onium radical and-.themetals'fofgroup -llof thelperiodictable.

Thns,,. cations thatare :suitable include .the ammonium fl radical, sodium potassiumrand-lithium :Of these cations,..the ammonium. radical and:sodium are preferred .ancl th en;latter..cation is particularly preferred. It .will

. be appreciated, of .-cour se,.,that these ..various salts may .be .used-;eithersingly-orin unison with one another.

.;.The sulfonates that 1 are utilized; inQthe compositions I .of :the presentinvention. are the salts. of ..alkyl.monocyelic and bicyclic aryl sulfonicacids wherein ,the ,cationic portion of,,the,,sulfonates. is preferably the. ammonium radical. Metals selected from group l or group 2 of the lperiodi'cltable such as sodium, potassium,.lithium, cal- I barium .rnay also benemployedj but the .am-..

mo niujm radical possesses unique advantages, partially tbccanse of ,its ashless, nature. Once again; these salts .may -"be used either separately, .jorin' combinationwith mammar- '2 1 sulfoni acidsthat may "be uti li zed in' the mate of j the present inventioninclude the oil-soluble petroleum sulfonicalcids that arederived from sulfonating petroleum stillate'. fractions with ,jsulfurioacid, sulfuric .trioxide, and the, like, Acids of .thiS- typethat. are particularly "etfective for thepurpos esof this invention includithose that possess molecular Weights within thefirange from l'aboutjOO, to'650fand especially' about 450 tosso. Acids of'thistcharacteriand their manner of preparation are lwe lL'k'n'own' in .the artand. a detailed discussion of these esent description. 7,

f jAQpreferredclass .of sulfonic acids for use, in"prep gthe above sulfonate. salts consis ts .of .the monojsulfonated alkylated mono-and/ or bi-cyclicaromatic sul- M yfonio-acids whichfare formed by.alkylating an aromatic nucleus"with analkyl radical and thereafter sulfonating the;alkyla ted productwith sulfuric acid. The resulting sulfonicacid isthen conveniently neutralized with am- 'monia"or 'an 'alkalijof one of'the'aforementioned de- 'siredmetals to form the corresponding, ammonium or. metal sulfonate salt. 'Any; excess or unreacted alkali, water, etc.,rnay 'be separated from the.pr.oduct bydecantationffiltration, OI thefQllkEffIIT general, it is 'pre- 'ferr'ed that the aromatic, nucleus of thefisulfonate" salts The alkyl group or groups of the alkylated' 'monoand bi-cyclic aromatic. compounds may. contain. antotal z-numberiof carbon. atoms.up.to..about..40, and the-group or groups may. be straight chain. and/or brancheddin structure. Preferred..sulfonic...acids..forzwuse in .th'e' linve'ntion are ones thatare...derived..f rom;rtheisulfonation of-:=mono-, di-,. and., tri-.alkyl substituted..- benzeneror .naphthalene. Compounds .that. are ,especially preferred for; sulfonation-ito the corresponding sulfonic-acids are thoseahavingthe structure 3R1 :wherein- R 'is a hydrogen atomor an 1 "alkyl group" that fea'tn es' is therefore not considered tobe necessary in.

Wgroupcontaining from about 12-24 carbonatomstw It will be noted that an alkylated naphthalene may be substituted for the alkylated benzene shown in the above}.

structure.

5 It is further preferred that the cumulative number" of carbon atoms among the alkyl groups of the alkylated;

acid of didodecyl benzene.

'15 Especially preferred ialkylmono aryl sulfonic acids are the acids that are formed by alkylating benzene with an olefin polymer such as polypropylene or polybutene or ,withcopolyrfners of propylene and butylenes, and

thereafter'sulfonating the resultingalkylate. The class of: compounds may thus be identified. as the polypropyli or; -polybutylbenzene sulfonic acids. Compounds of -,this typearewell-known in; the-art as well as the methods --for;,'theirmanufacture.-;Insofar as the present invention is concerned, the .compounds of this type that are-of wespecial interest-are, the compounds wherein the alkyl ;groups are-derived from olefin polymers and contain,

'from- 9.118 .carbon atoms each andespecially about 12 carbonr atoms, the total number of alkyl carbon atoms 'tin anycgiven benzene; sulfonic acid being 40 or less,. -preferably l2+36,-and;especially about 24. An espe c ;i ally,-pr.efer-red compound of this type for -use ingthe 9 tetrapropylene. in 100% concentration or may be diluted for-convenience .using,,.for.example, adistillate fuel. The diluent should spres ent..-invention is .the ammonium salt of didodecyl benzene sulfonic acid wherein the alkyl radicals are 1 p The ammonium sulfonatemay be used .be aclean-burning hydrocarbon, preferably a straight run petroleum distillate.

Asiindicated earlier, the.present;i-nventionutilizes. a .freaction product which isv .formed .by, reacting, an' inorganic salt of a. type des'cribedhereinabove with asul- ..fona te .of a. type also des cribed hereinabovef- .This reaction is preferably carried out by admixing proportions of nan aqueous solution ofone onrnore of the inorganic 'salts,,with -anoil solutionofone or more of the sulfonates and thereafterheating the resulting ,mixture at a temperature. and for a period of time sufiicient to vvaporize all of the water from the mixture. Temperatures and reaction times that aresuitable for this reaction. depend to some extent upon the amount of water present. in the reaction mixture, but reaction times of about 30 to 240 minutes and-temperatures above 230 F.. (,preferably. about 300 are, eflective for the pur- I pose.

The concentrates 'ofthe inorganic salts and the sulfo nates .within the respective aqueous. and oil solutions have not been 'found.to be criticalto the successof the "inven- Jtion; but ity is generally contemplated that substantially saturated solutions of the inorganic salts'and oil solutions containing about 25 to 100 wt.'.percent of the sulfonates are preferred; The solvents employed in the oil solutions of the sulfonates may include any conventional 'cleani burning petroleum distillate fraction and are conveniently 1 petroleum fractions that boil in substantially the same are to beeventually blended.

The proportionsof inorganicsalts and sulfonates withinthereaction involving these two compounds shouldbe such as to provide about 0.1 to 4.0;mols of inorganic 70j salt per mol of sulfonate and preferably about 0.5 to'2.5 I

mols. of inorganicsalt per 'molof sulfonate.

The structure of the reactionproduct that is formed by admixing and heating-the inorganic salt and the-sulfonate in'the manner described above is not presently? known,

75.-butit appears that'a coordinationccomplextofesome.sort' boiling range as the fuel oil components with which they is formed which possesses the very desirable quality of bemg very soluble in distillate petroleum fractions of the type of interest here. It should be noted at this point that a portion of the inorganic salt may fail to go into solution during the reaction period, and this insoluble portion should be separated, as by filtering or centrifuging, from the reaction product before the latter material is incorporated within a distillate fuel. I

The complex reaction product may be incorporated in a distillate fuel oil of a type described earlier herein by any suitable conventional procedure. Thus, propeller mixers, micronizers, I conventional stirring devices, etc. and mild-heating may be employed for this purpose. It is important, however, that a suflicient portion of the reaction product be incorporated in the fuel oil so as to achieve the objectives of the invention. The exact amounts required for this purpose may vary slightly depending upon the nature of thelfuel oil; but an amount in excess of about 0.002% by weight of active ingredient is generally required. Amounts. of the reaction product up to about 0.3 .wt. percent may be employed, but the advantages of the invention are bestrealized with amounts of about 0.0lto 0.10 wt. percent and especially about 0.02 wt. percent based on active ingredient.

While the foregoing description hasbeen concerned with a preferred procedure wherein an aqueous solution of an inorganic salt is reacted with an oil solution of a sulfonate, it will, be appreciated that variations from this procedure may be resortedto without departing from the spirit or scope of the invention. Thus, it is possible. that the inorganic salt may be introduced directly Within the sulfonic acid salt solution in dry form without utilizing an aqueous solution of the salt. Furthermore, in some instances, it may be desirable to employ an alcoholic solutionof the salt rather than arraqueous solution. Again,

it may be desirable to form the complex reaction product directly within the distillate fuel oil itself; and it may also be desirable to aid water removal from the reaction mixture by bubbling a dry gas such asnitrogen or the like through the reaction mixture during the heating period. r

. It will also be appreciated that a number of other conventional fuel oil additives such as drying agents, color stabilizers, demulsifying agents, oiliness agents, etc. may also be incorporated within the present compositions so long as these other materials do not interfere with the objectives of the invention.

In order to better illustrate the nature of the present invention, attention is directed. to the following examples wherein samples of a distillate fuel oil were evaluated with particular reference to their sediment stability, color hold and corrosion inhibiting qualities; The samples of fuel oil in some instances contained no additives and in other instances contained additives of the prior art. In still other instances, samples of the fuel oil were provided with the complex reaction product additives of the type described in the present invention. l

The distillate fuel oilthatwas employed inthese examples had the following physical characteristics:

The fuel oil was furthermore characterized by containing about 50 vol. percent straight run stocks, 40-45 vol. percent stocks from catalytic cracking operations and 5-l0' vol. percent stocks from thermal cracking operations.

6 EXAMPLE I In afirst series of tests, samples of the above fuel oil were evaluated alone and also in combination with several additives. For the sakeof clarity, these additives are described separately in the following paragraphs and are designated by the letters A,B and C in order to further simplify the description. One of the additives employedin this example was the ammonium salt of an alkylated monocyclic aryl sulfonic acid of about 450 molecular weight. This additive consisted principally of ammonium didodecyl benzene sulfonate in about 40 wt. percent concentration in a straight run kerosene fraction. The additive is hereinafter referred to as additive A.

The second additive employed inthe example was a complex reaction product formed by reacting 20 parts by weight of sodium nitrite (dissolved in 30 parts by weight of water) with parts by weight of the above ammonium sulfonate (in 40 wt. percent concentration in a kerosene of 39 API and 325 550 F. boiling range). In the preparation of this additive, which constitutes an additive of the present invention, the mixture of aqueous nitrite and sulfonate was heated to a temperature of 300 F. with continuous stirring and with a light nitrogen blowing operation for a period of about one hour in order to remove water from the reaction mixture. Following the reaction period, the mixture was filtered to remove unreacted sodium nitrite. The resulting product was clear and contained about 5.7% by weight sodium and about 4.0% by weight sulfur. The calculated composition of this product, based on the analysis and the approximate molecular weight of 450 for the original ammonium sulfonate, is about 74% active ingredient of the reaction product of ammonium sulfonate and sodium nitrite and about 26% of the kerosene diluent. It will be noted that a portion of the kerosene is normally lost during the water removal operation, but this loss does not adversely affect the formation of the desired reaction product in any way. It will further be noted that this additive is hereinafter designated as additive B.

The third additive employed in this example was a prior art additive containing sodium petroleum sulfonate in combination with an alkyl phenol sulfide. The sodium sulfonate in this instance was the sodium salt of a petroleum sulfonic acid of about 500 molecular weight, and the phenol sulfide was present in the form of the salt of an alkaline earth metal. The additive furthermore consisted of about one part by weight of the sulfonate per two parts by weight of the phenol sulfide. This additive is hereinafter referred to as additive C.

In this example as will be described in detail, the various fuel oil compositions were evaluated in .accordance with several methodsboth. as to their sediment stability and color hold and also as to their ability to inhibit the corrosion of ferrous metals.

In a first procedure, samples of the fuel compositions were heated for a period of about 16 hours at 210 F. and the sediment formed during the storage period thereafter recovered and weighed. It has been determined by an extensive number of samples that results from this test procedure correlate with actual sedimentation results that occur in fuel oils of this type during extended storage periods in actual storage tanks, domestic heating oil tanks, etc. I

The corrosion inhibiting qualities of the various fuel samples were determined in accordance with a laboratory test procedure which has also been found to correlate with the actual field results that have been experienced by refiners and consumers of these products. In accordance with this procedure, a sample of fuel is vigorously admixed with about 5 vol. percent water (either distilled or synthetic sea water prepared as per ASTMD665 52T), and the resulting mixture is thereafter separated into an equilibrated oil layer and an equilibrated water layer. Each of the layers is reserved for subsequent use in the test.

For each fuel sample, a hot-rolled steel panel having its surface uniformly covered .with an roxidizedufilm ror -mill.;scale is...used. .1 Small spaced.-por,tionstofgthe :surface ofthe-steel-panel or=test-;sampleare descaled-asiby scratching or milling'throughe the scale. layer. A-droplet of.equilibratedwatertfrom,the: mixing. operation described above is .then placed :directly.:on,a:part 10f each rarea of exposed fresh .metal -.;surface \"in... such ,a way ;-:,that .the droplet also covers apart of the farea 50f .metal ;still covered with the. deposi-tedifilm;

. Each steel panelor-samplexwithiitsadhering droplets of .water is then .stored for. a'perio.d of;2l days-submerged beneath the :SHIfflC6Of":th6 :equilibnatedoil. :Each point where a droplet is.-in.contact :;with1theibaredrmetalplate 'isIconsidered as;-.a:poss'iblessite ofrcorrosion, andaa total of about 1 to '16.corrosion.:sites;isrgenerally observed on each plate.

' This.arrangement.of::oil and twater, each'contacting a portion of each .of 'the areas of exposed 'or' film-covered metal, particularly favors lthe development .of pitting corrosion which rprobablyeccurs through-a mechanism involving electrical concentration cells. -:Pitting of actual metal surfaces .instoragetanks isconsidered to proceed by this 'typ'e of mechanism.

Following the storage time, each steel panel-is removed from the oil and washed with pentane and acetone solvent. Each washed plate is then wire Ebrushed to remove rust from the corrosion .sites .and is thereafter dried.;and weighed to determinethe amount of metal lost due to.,corrosion. Theydepth of maximum corrosive penetration. at each corrosion; site is determined by means .of a'microscope whiehzis eguipped'with afocusing dial calibrated in 'milliinches.

An additional test thatwasperforrned on each oil composition I was :.a .color'rholds test carriedout in accordance with the following-procedure. -A ;sampleof about .20 cc. of an oil .-composition :-is ;-placed.,in the sample tube o'f a suitablezcolorimeter ;(a;suitab,le instrument ,is the Hellige Diller Photoelectric .Colorimeter.Model-.No. 400). With the sample in the sample tube, the instrument is adjusted to transmit white light through the sample, and suitable adjustments are made to indicate 100% light transmission for t-he fresh oil sample as a standard. A previously prepared sample of heat-treated (210 F. for .16 .hours) and filtered oil from the same compositionis then introduced into a sample tube and the percentilight transmission again read from the instrument. The color hold value vis then the percent light transmission through the heated and filteredtest sample relativeto the fresh sample, considering the latter sample to possess 100% light transmission.

The results that were obtained by subjecting the aforedescribed fuel compositions-Pi. e. the fuel oil itself and in combination with additives A, B and C-are presented in the following table.

T bl I STABILITY AND CORROSION CHARACTERISTICS OF FUEL OIL COMPOSITIONS Additive Base .A B .0

Fuel

Additive Concentration: Wt per- 7 cent Active Ingred 0.025 0.022 0.02 Storage Test, 16 hrs. 210- iment, Inge/600 g. oil 41.7 155. 1.7 Color hold, 16 hrs. 210 IE: Percent Transmissi n 58 8 71 Pitting'in Distilled 'Water:

' AvHM-ax. Penetrati n, Mils 3. 5 0 0 4.8 Range-0f Max. Penet., .Mils 2,5 0 0 2-11 'Wt', loss per site, mgs 7. 3 1 7. 7 0 1.6 No. of possible corrcsi msit 2 32 14 Fitting in Synthetic Sea Water:

Av. Max. Penetration, Mils 1. 7 1 0 2.2 Range of Max. Penet., Mi1s 2-5 1 0 2 3 Wt. Lossper site, mgs 6. 4 1. 4 0v .5.1 No. of possible corrosion sites 20 2 32 22 Weight loss without pitting is primarily due to uniform corrosion of exposed metal areas.

' the'presentmethod -for ;a' number of obyiousfreasons."

. 8 1 It-is-readily apparent fronrthe'above 'table"thatfthe' complex -reaction "product additive of the present jinve'ni tion is extremely effective in "stabilizing *aiiistillate oil, insofar as its 'sedimentationand colorhold 'cliara'cte istics are concerned". It is further apparent-that th complex additive 'is extremely -e'lfective inreducingfthg degree of pitting corrosion that has otherwise been; observed to occur in the presence jof ferrousmetal'sr"" It will further be observed that-ammonium sulfonatg alone, as representedby sample A, possesses reasonably satisfactory pitting corrosion characteristics; but this: additive is substantially"ineffective in reducing sediment formation "and"colorholddepreciation. It will be 'apprefi ciated that this particular additive has been suggested in the prior art-"forusefas asediment stabilizing'additive in distillate fuels, butinthe particular'fue1 tested"here and in the "additiveconcentratio'n employed, this adiiit actually "was detrimental in its "effect rather than-1 beneficial. f Table '1 'above further'demonstrates that theadditives of "the present" invention are superior to another priorart additive-namely, an additive mixture of sodium petro leum sulfonate and the metal salt of an alkyl :pheno sulfide. The latter additive "has previously been demon strated to possess good sediment and *col'orhold stabilizing properties, "butfit is "markedly inferior to the pres: additive composition 'in reducing pitting corros'ion.

At this pointit is we'llton'ote"that-'the"complex-addi tives of the present invention are alsos upcrior'ito an inorganic salt" alone such as sodium nitrate in that {salts o'fithis typeare not'solublein distillatemineral-oils. *It'. is conceivable, of course, that -*layers {of water "within storage tanks 'and' the like could be provide'd 'with inor-f, ganic corrosion "inhibitors such as 'sodium nitrite, be! this -mode of corrosion prevention isfpat'ently infer ior to' "What is ,claimed is: '1. An improve'dfue'l composition corrrprising'a'in for" proportion of distillate petroleum hydrocarbons-and' minor but sediment-stabilizing and 'rust inhibiting proportion of .an oil-soluble complex formed by reac'tirlg ilv water-soluble salt ,of nitrous acid with an oil-soluble U ammonium sul-fonate, the cationic portion of'said'nitrite being'selected'from'the class'consisting of the" ammonium f radical, sodium, ,lithium and potassium, the sulfonate' being selectedfromthe class-consistin gpf the ammonium salts of the alkyl monoand jbiCyCllC *aryl sulfonic 3 acids, said complex *being'formed by conducting said 1 reaction at a temperature and-for aperio'd of timesu'ffi cient toremove 'all of the water from the" reaction mixture. a 2. A composition 88 defined in claim 1 in which alkyl portion of ,the 'sulfonate contains up to about-40 carbon atoms. v I 3. A composition as defined in claim l-in'which complex is formed by reacti g about 01 to 40mph o1 the nitriteper mole of sulfonate. v f 4. A composition asidefi nedlinclaim lfin w'hic h the reaction product constitutes'from about 0.002 to 0.3 wt. of said composition. 7 I 1 1 5. A composition as-defined inc-laim '1 in -whichthe nitrous acid"saltis'sodium"nitriteand the sulfonateis ammonium'didodecylbenzene-sulfonate. 6. A composition as definedin claim 1-in which'- th nitrite is ammonium nitrite and the sulfonate is arnjmonium didodecyl benzene 'sulfonate. '7. A composition as defined in claim 2 in "which-the V alkyl portion is derived from the polymerization of olefin.

.8. An improved fuel .composition'comprisi'ng a major proportion ofdistillate petroleum hydrocarbons including at least about 10% cracked stocks anda minor propor; tion .of an oil-soluble comp ex a d. m il i 0 formed by reacting an aqueous solution of a water soluble nitrite with an oil-soluble ammonium sulfdnate;

the cationic portion of the nitrite salt being selected from the class consisting of the ammonium radical and the alkali metals, the sulfonate being selected from the class consisting of the ammonium salts of alkyl monoand di cyclic aryl sulfonic acids, the reaction product being present in an amount less than 0.3 wt. of said fuel composition but sufficient to prevent sediment formation and to inhibit the corrosion of metals with which the composition comes in contact, the reaction product being formed by conducting said reaction at a temperature and for a period of time sufficient to remove all of the water from the reaction mixture.

9. A composition as defined in claim 8 in which the sulfonate is derived from a petroleum sulfonic acid of about 300 to 650 molecular weight.

References Cited in the file of this patent UNITED STATES PATENTS Talbert et a1; Sept. 15, 1942 Wachter Sept. 29, 1942 Carom et al Oct. 31, 1950 Assefi et a1. Nov. 4, 1952 Mertes Dec. 23, 1952 Kronig et a1. Aug. 25, 1953 Assett' et al Nov. 30, 1954 Rogers et a1 Apr. 17, 1956 FOREIGN PATENTS France Feb. 18, 1954 

1. AN IMPROVED FUEL COMPOSITION COMPRISING A MAJOR PROPORTION OF DISTILLATE PETROLEUM HYDROCARBONS AND A MINOR BUT SEDIMENT-STABILIZING AND RUST-INHIBITING PROPORTION OF AN OIL-SULUBLE COMPLEX FORMED BY REACTING A WATER-SOLUBLE SALT OF NITROUS ACID WITH AN OIL-SOLUBLE AMMONIUM SULFONATE, THE CATIONIC PORTION OF SAID NITRITE BEING SELECTED FROM THE CLASS CONSISTING OF THE AMMONIUM RADICAL, SODIUM, LITHIUM AND POTASSIUM, THE SULFONATE BEIN SELECTED FROM THE CLASS CONSISTING OF THE AMMONIUM SALTS OF THE ALKYL MONO- AND BI-CYCLIC ARYL SULFONIC ACIDS, AND COMPLEX BEING FORMED BY CONDUCTING SAID REACTION AT A TEMPERATURE AND FOR A PERIOD OF TIME SUFFICIENT TO REMOVE ALL OF THE WATER FROM THE REACTION MIXTURE. 